Excitation effects on LSO unit sustained responses: point process characterization

LSO units recover from a spike discharge in a characteristic way, modeled by an intrinsic recovery function that is stimulus invariant up to a scaling factor and a shifting constant. Data analysis shows that the effect of increasing excitatory stimulus level can be described by amplifying the intrinsic recovery function and by shifting it toward shorter intervals. The shifting process secondarily interacts with the absolute deadtime to produce the response characteristics of the three LSO unit types. Decreased excitation is clearly distinguished from inhibition, which affects the scaling, but not the time origin, of the recovery. We conclude that both excitatory and inhibitory stimulus levels are encoded in the timing of LSO unit discharges.